Flexwood spring for chair seats



Nov. 23, 1943. A. J. SCHAFFNER 2,335,160

FLEXWOOD SPRING FOR CHAIR SEATS Filed Dec. 30, 1942 2 Sheets-Sheet l INVENTOR.

Nov. 23, 1943. A. J. SCHAFFNER FLEXWOOD SPRING FOR CHAIR SEATS Filed Dec. 30, 1942 '2 Sheets-Sheet 2 :16 51 I i w w In!" 2O 12 gfiwp wit/L655 A6 27 23 25 14 MW n-Z @Mgx 5E3 Patented Nov. 23, 1943 FLEXWOOD SPRING FOR CHAIR SEATS Alvin J. Schaflner, Aurora, 111., assignor to Kroehler Mfg. Co., Naperville, 111., a corporation of Illinois Application December 30, 1942, Serial No. 470,552

2 Claims.

This invention relates to a laminated flexwood spring for chair seats, and has for its principal object to provide a novel and improved leaf spring construction made of laminated flexwood which may be readily applied to a chair seat and which will give to said seat the required resilient flexibility heretofore provided by the use of steel coiled or other steel springs.

A further object of the invention is to provide a flexwood spring construction for chairs affording a greater range or degree of flexibility than is attained by spring arrangements of a somewhat similar character heretofore proposed. More particularly, the present invention constitutes an improvement in some respects over the construction disclosed and claimed in my copending application, Serial No. 443,249, filed May 16, 1942, which has resulted in Patent No. 2,316,628, issued April 13, 1943.

The advantages of the invention will appear more fully as I proceed with my specification.

In the drawings:

Figure l is a perspective View of a chair of any familiar construction, with the upholstered seat containing the improved flexwood spring of the invention.

Figure 2 is an enlarged vertical section in a plane indicated by the line 22 of Figure 1, with the upholstery of the seat removed.

Figure 3 is a fragmentary perspective View of the chair frame showing the lower spring unit attached thereto.

Figure 4 is a perspective view showing both the upper and lower spring units removed from the chair frame.

Figure is a fragmentary top plan view.showing one end of the chair frame with both spring units applied thereto.

Figure 6 is a front view of the chair frame with parts broken away to show the spring units in assembled relation therein.

Referring now to the embodiment of the invention illustrated in the drawings, Figure 1 shows an upholstered chair having a frame made of wood in the usual manner. I2 indicates the front rail, and I3, I3 the side rails of the frame. The rear ends of the side rails I3 are connected by a horizontal frame member I4 adjacent the bottom of the frame. The frame may also in-- clude a pair of upstanding front corner posts I5, I5 and rear corner posts I6, I6 which are connected by upper side rails I1, I! spaced slightly above the side rails I3, I3. A cross bar I8 is connected between the rear ends of the upper side rails I1, I! adjacent the rear upright posts I6 so as to be parallel with, but spaced substantially above, the first named frame member I4. A pair of upright back supports I9, I9 may also be secured along the inner faces of the rear upright supports I6, I6, in the form shown said upright back supports having their lower ends connected to the cross bar I 8, as shown in Figure 3.

I also provide a plurality of upright guide members 20, 20 disposed in laterally spaced rela-' tion with each other so as to form a plurality of upright slots in the space formed between the lower rear frame member I 4 and the cross bar I8 at the rear end of the frame. In the form shown herein, said guide members 20, 20 have their upper ends connected to a cross bar 2I having its ends suitably secured in the frame as by connection to the upright back supports I9, I9 immediately above thecross bar I8 (see Figures 2 and 3). The purpose of the slots be tween these upright guide members will presently appear.

The spring structure of my invention is preferably made up of two separate units, the lower spring unit being indicated generally at 23, and the upper unit being indicated generally at 24. The lower spring unit 23 consists of a plurality of laterally spaced. parallel flexible spring leaves 25 attached at their front ends to an anchor bar 26 and curving upwardly and then rearwardly toward their rear ends, which are guided for relatively free vertical movement in the slots formed between the upright guide members 20 at the rear end of the frame. The anchor bar 26 is rigidly connected to the chair frame as by securing its opposite ends to the inner surfaces of the side rails I3, I3 at a suitable point toward the front of the chair. The lower spring unit may therefore be more or less permanently mounted in the chair frame. In connection with the lower spring unit, I also provide an auxiliary support bar 21 spaced rearwardly and below the level of the anchor bar 26 in position to be engaged by the spring leaves 25, 25 when said spring leaves are placed under tension.

The upper spring unit comprises a plurality of laterally spaced, parallel, flexwood spring leaves 39 attached at their front ends to a depending rocker bar 3| which extends transversely of and depends below said leaves. The spring leaves 3!] of the upper unit correspond in number with the spring leaves 25 of the lower unit. The leaves 33 are arched upwardly intermediate their ends, and their rear ends are adapted to be disposed upon and engage the free ends of the leaves 25 of the lower spring unit in the slots formed between the upright guide members 20, 20, as shown in Fig ure 2.

The upper spring unit is completed by a plurality of laterally spaced, parallel, flexwood spring leaves 32, each of which is secured at its rear end on the upwardly arched, intermediate portion of one of the spring leaves 30, and with its forward end curved upwardly and attached to a strip 33' extending transversely across the front of the upper spring unit.

' The front rail [2 of the chair seat is provided along its upper edge with a rounded groove 35 in which seats the rocker bar 3!, which has a correspondingly transversely rounded bottom edge. The upper spring unit 24 as thus described may be assembled or disassembled as a unit in the chair frame by inserting the rear ends of the spring leaves 30 in the upright slot formed between the guide members Zll at the rear of the frame, and resting on the corresponding rear ends of the spring leaves 25 of the lower spring unit 23. The rocker bar 3| is fitted in the grooves 35 of the front rail l2, as shown in Figure 2.

Suitable upholstering. material may be applied along the. uppersurface of the upper spring unit 24 in any suitable manner, as indicated in Figure 1.

It will be understood that straight grain woods and semi-fiexible waterproof glue may be used in the manufacture of the laminated spring leaves. They are given the. required form. or shape and are so treated-inla familiar manner that when finished they maintain their shape and form equally as well as similar springs manufactured. from steel.

Although I have. shown and described one particular embodiment of my invention, it will be understoodthat I do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of my invention; as defined in the appended claims.

I claim as my invention:

1. A fiexwood spring construction comprised of upper and lower units, the lower unit comprising a plurality of laterally spaced flexwood spring leaves having their forward ends connected to an anchoring member, and their rear ends being relatively free, the upper unit having a like number of laterally spaced flexwood spring leaves arched upwardly intermediate their ends, the front ends of said arched leaves being fixed to 2. depending rocker bar, and the rear ends of said arched leaves being adapted to rest on the corresponding leaves of the lower spring unit, said upper unit also having aplurality of spring leaves. each of which is secured at its rear ends on the upwardly arched intermediate portion of one of said arched spring leaves, and with its forward end attached to a transverse strip defining the upper front edge of said upper spring unit.

2. A flexwood spring construction comprising an upper frame having front and back rails, upper and lower spring units comprising a plurality of laterally spacedv ilexwood spring leaves having their forward ends connected to a transverse anchoring member fixed on saidframe, and their rear ends being relatively free, the upper unit having a like number of laterally spaced iiexwood spring leaves arched upwardly intermediate their ends, the front ends of said arched leaves being fixed to a depending rocker bar, and the rear ends of said arched leaves being adapted to rest on the corresponding leaves of the lower spring unit, said upper unit also having a plurality of spring leaves, each of which is sccured. at its rear ends on the upwardly arched intermediate portion of one of said arched spring leaves, and with its forward end attached to a transverse strip definingthe upper front edge of said upper spring unit, and said back rail being provided with upright laterally spaced slots through which the rear ends of the leaves of both the upper and lower spring units extend for relatively free vertical movement.

ALVIN J. SCI-IAFFMER. 

